Dynamic MRI (dMRI) as a guide to therapy in children and adolescents with persistent full thickness rectal prolapse: a single centre review

Rectal Prolapse in the Pediatric Population

PURPOSE OF REVIEW

Rectal prolapse in the pediatric population presents a clinical challenge with wide variability in etiology, presentation, work-up and management. In this article, we reviewed the evidence supporting various medical and surgical treatment options as well as the recent trends amongst pediatric surgeons.

RECENT FINDINGS

Medical therapy is highly effective in most patients, with bowel management programs being particularly successful. Nonetheless, medically refractory disease, often seen in older children and in children with behavioral/psychiatric disorders, can be challenging. Sclerotherapy with ethanol or 5% phenol can be effective local treatments. 15% hypertonic saline, 50% dextrose, and Deflux are additional safe alternatives. Perianal procedures and perineal procedures are less invasive surgical options, but transabdominal rectopexy appears to be the favored treatment for disease refractory to local treatment. Transabdominal rectopexy with sigmoidectomy, the recommended operation in the adult population for patients with prolapse and constipation, appears only to be preferred in the pediatric population for postoperative recurrences.

RECENT FINDINGS

While outcomes of medical treatment for pediatric rectal prolapse are excellent, sclerotherapy and transabdominal rectopexy are effective options for refractory disease preferred by most pediatric surgeons.

MRI anatomy of anteriorly displaced anus: what obstructs defecation?

BACKGROUND

Anteriorly displaced anus is an anomaly that is debated with regard to its nomenclature, diagnosis and management.

OBJECTIVE

To describe MRI anatomy of the anal canal in children with anteriorly displaced anus and its impact on the process of defecation.

MATERIALS AND METHODS

We prospectively examined ten children (7 girls, 3 boys; age range 7 months to 8 years, mean 3 years) with anteriorly displaced anus between August 2009 and April 2012. Noncontrast MRI examinations were performed on a 1.5-T magnet. T1- and T2-weighted turbo spin-echo images were acquired in axial, sagittal and coronal planes of the pelvis. The anorectal angle and the relative hiatal distance were measured in mid-sagittal images, and compared with those of a control group using the Mann-Whitney test.

RESULTS

In children with anteriorly displaced anus, no anatomical abnormality was depicted at the level of the proximal anal canal. However, the distal anal canal was displaced anteriorly, running out its external muscle cuff, which remained un-displaced at the usual site of the anus. This changes the orientation of the central axis of the anal canal by passing across instead of along the fibers of the longitudinal muscle coat. Children with anteriorly displaced anus had a more obtuse anorectal angle (mean 112.1°), which was significantly greater than that of the control group (mean 86.2°).

CONCLUSION

MRI is a valuable tool in studying the anatomy of the anal canal in children with anteriorly displaced anus. The abnormal orientation of the longitudinal muscle across the anal canal can explain the obstructed defecation in these children. Based on this study, it might be of interest to use MRI in studying equivocal cases and children with unexplained constipation.